Power fluid conditioning unit

ABSTRACT

A one well, self contained, wide producing range, hydraulic pumping system comprising a power fluid conditioning unit to condition produced water, oil, or a mixture of oil and water, from the produced well fluids and exhausted power fluid so that it will be suitable for use as power fluid to economically pump a well which produces medium to large volumes from average to greater depths of lift.

United States Patent 1 Palmour [451 Jan. 9, 1973 [54] POWER FLUID CONDITIONING UNIT [75] Inventor: Harold H. Palmour, Humble, Tex.

[73] Assignee: Armco Steel Corporation, Middletown, Ohio [22] Filed: April 8, 1971 [21] Appl. No.: 132,361

[52] US. Cl. ..166/68, 166/1055, 417/80 [51] Int. Cl. ..E2lb 43/00 [58] Field of Search ..l66/68,105.4,105.5,105.6; 417/77, 79-83 [56] References Cited UNITED STATES PATENTS 2,080,622 5/1937 McMahon ..l66/105.5

2,081,225 5/1937 Coberly ..l66/l05.5 2,763,281 9/1956 Morgan ..417/80 3,260,308 7/1966 Cryer ..166/68 3,578,077 5/1971 Glenn.... "166/68 Primary Examiner-James A. Leppink Attorney-Melville, Strasser, Foster &- Hoffman [57] ABSTRACT 9 Claims, 6 Drawing Figures PATENTEDJAM 9197s V 3,709,292

' sum 1 [If 4 l NVENTO R/S mymzhww ATTORNEYS PATENTED JAN 9 I975 SHEET 3 BF 4 lNVENTOR/S 1/4620 name BY ;%m, Zn M/ ATTORNEYS POWER FLUID CONDITIONING UNIT BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to hydraulic pumping systems, and more particularly, to a hydraulic pumping system which is economically applicable for the average to greater depth wells which are producing only moderate to large volumes of well fluids.

2. Description of the Prior Art It is becoming increasingly rare when the plans for the producing phase of oil fields do not include a water flood. Often water injection is begun immediately as a means of maintaining bottom hole pressures and thereby extending the flowing life of the field. In any case, as a well of this type goes on the pump, it can be assumed that large quantities of water will have to be produced with the oil and that the total volumes to be pumped will gradually increase as the percentage of water increases. I

Hydraulicdownwell pumps disposed at the lower ends of wells are especially suited to these installations, as their capacity may be controlled by varying their speed, and this being affected by simply adjusting power fluid flow. An additional advantage of hydraulic pumps is being able to retrieve a free type hydraulic pump by circulating it out' of the well. Such retrieval becomes even more important when inspection or repair is necessary due to the adverse environment which is often encountered. a

The oil industry today is also concerned with deeper drilling, off shore development and continued activity in the formation of large secondary recovery projects. With each of these trends, when artificial lift. is

required, it will be desirable to have a lift system capalarger volumes of power fluid to be'directed to these units in orderto provide the additional energy required.

While water has heretofore'been utilized'as apower fluid, its use has been in multiple well installations where central'power plants, treating facilities, tankage and controls are at one location, requiring high pressure power fluid lines out to each well to conduct the power fluid to that well. Its use has also been in closed power fluid systems, wherein the power fluid is kept separated from the well fluids and-thereby requires a separate string of pipe to return the exhaust or spent power fluid back to the surface and a return line from the well back to the central station. In addition to the While the prior art has successfully used both power water and power oil as hydraulic fluid to operate subsurface hydraulic pumps, such use has been with multiwell installations or in closed power fluid systems where the power fluid is kept separated from the well fluids, and not with a one-well, self contained unit that has universal application to produce solid free power fluid.

SUMMARY OF THE INVENTION The present invention provides a one well, self com I tained, hydraulic pumping installation for a pumping system of the type having a downwell pump which utilizes produced water, oil, or a mixture of oil and water, as the power fluid for pumping well fluids. The pumping installation comprises a power fluid conditioning unit to condition produced water, oil, or a mixture of oil and water, which is always under pressure above atmo'sphere, from the produced well fluids and exhausted power fluid so that it will be suitable for use as power 'fluid. Briefly, the produced well fluids and exhausted and high pressure conditioned fluid is discharged from the power fluid outlet of the pressure pump and down the well to operate a sub-surface production unit, such as a downwell hydraulic pump.

The volume of oil, gas and water a well is producing is discharged from the separator-accumulator tank into a flow line which leads to further processing units.

Solids separated by the cyclone separator are discharged with some fluid directly into the flow line and join-the production of the well.

The power fluid conditioning unit of the present. invention provides a one-well syner getic lift system which is safe, flexible and an economical method of producing an oil well. Since the power'fluid conditioning unit power fluid, high pressure distribution lines to the wells of the present invention combines the spent power fluid with the fluid'at the bottom of the hole and then separates conditioned power fluid inthe power fluid conditioning unit, it saves the surface piping as wellas a string of tubing from the bottom of a hole, whichare required, for example, with existing closed central systems serving many'wells. The power fluid conditioning unit of the present invention keeps the power fluid under pressure at all times and thus it is not exposed to air where it can pick up oxygen and be more corrosive, as is the case with other closed water power systems. It eliminates the cost associated with a sucker rod pumping system. In addition, it eliminates (l) the inventory of power oil, (2) the power oil tank, (3) high pressure power oil lines, (4) fire hazards, and (5) additional treating facilities necessary at the central battery of the usual closed central system. The power fluid conditioning unit of the present invention may be tailored to fit the requirements of a well with'a maximum flexibility for producing rates or well changes and it may be 3, quickly installed because it does not entail a major construction job at the lease.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic flow diagram showing a one well, self contained, hydraulic pumping system according to the present invention.

FIG. 2 is a perspective view showing the skid mounted power fluid conditioning unit of the present invention.

FIG. 3 is 'a cross sectional view through an exemplary separator-accumulator tank which forms a part of the power fluid conditioning unit of the present invention.

FIG. 4 is a cross sectional view taken on the lines 4 4 of FIG. 3.

FIG. 5 is a perspective cross sectional view showing an exemplary cyclone separator which forms a part of the power fluid conditioning unit of the present invention.

FIG. 6 isa graphical summary (maximum pump displacement vs. pump setting depth) of the results of a testing program on the power fluid conditioning unit of the present invention as utilized with a variety of downwell hydraulic pumps at differing pump setting depths.

DESCRIPTION OF THE PREFERRED EMBODIMENT Turningfirst to the schematic view of FIG. 1, it will be seen that a typical well 10 is provided with a standard wellhead'control 12 communicating with a subsurface production-unit, such as the downwell pump 14, which'utilizes water, oil, o ra mixture'of oil and water, as the power fluid, for pumpingthe well. The power fluid intake is illustrated at 16 and the produced well fluids and exhausted power fluid are illustratedat l8. The present invention provides a one well, selfcontained, hydraulic pumping installation comprising a power fluid conditioning unit 20 to condition produced fluid from the produced well fluids and exhausted power fluid solthat it will be suitable for use as power fluid. Theconditioning unit 20'include's' a pressurized separator-accumulator tank 22, including a back pres-' sure valve 24 for controlling the pressure therein, a cyclone centrifugal separator 26, power driven pump means 28, and means for controlling the speed of the downwell pump 14 in the well 10, by controlling the power fluid flow, such as the valve means 30 which bypasses a quantity .of clean power fluid back to the intake of the cyclone separator 26. Additionally, means 66, such'Ias a chemical pump,.may. be provided for discharging chemicals into the suction of the pump means 28, such as an electric motor driven multi-plex plunger pump 60,-so that the clean power fluid passing therethroughacquireslubricating, non-corrosive and other desired power fluid qualities. If necessary, a gas eliminator 31 may also be provided between the cyclone separator'26 and the pump means 28. g

The produced well'fluids' and the-exhaustedpower fluid 18 are pumped from the well 10 into the pressurized separator-accumulator tank 22, which is designed basically as a free-water knockout, wherein the gravity separation of water from oil and gas takes place. The separator-accumulator tank, as best seen in FIGS. 3 and 4, is provided with at least two main outlets therein, a first outlet 34 communicating with the flow line 36, which leads to the lease treating facilities and tank battery (not shown), the volume of oil, gas and water produced by the well 10 being discharged therethrough, and a second outlet 38 in the lower sec- 4, the separation of the produced well fluids and the exhau'sted power fluid in the tank 22, into gas, oil and water is indicated by the numerals 40, 42 and 44, respectively. Y

A back pressure valve 24 is positioned between the flow line 36 and the tank 22 for controlling the pressure in the tank 22.

At least one cyclone, centrifugal separator 26 communicates with the second outlet 38 in the lower section of the tank 22 so that the cyclone separator 26 will receive fluid from the lower section of the tank 22 at an optimum pressure (controlled by the back pressure valve 24) to give a desired pressure drop there across for the requirements of a particular well.

As can best be seen from FIG. 5, the cyclone separa tor 26 is provided with an inverted conical section 48,

which may, as desired, includean upper vertical side 26. An inlet 52 on the side wall of the cyclone separator 26 communicates with the second outlet 38 of the tank 22. The inlet 52 is adapted to direct. the inlet flow of fluid to be conditioned from the tank 22 substantially tangentially to the inner surface'of, the cycloneseparator 26. An outlet 54 for conditioned fluid from the cyclone separator 26 is provided in the upper end thereof. In operation, 'pressurized fluid to be cleaned entersthe inlet 52 and rotation thereof, as indicated by the arrows 56, develops high centrifugal forces-in the cyclone separator 26, drawing suspended solids out-' ward'toward the wall'fof the conical section 48 and downward in an accelerating spiralalong the wall to'the solids discharge point at the apex 50 and moving condi tioned water inward and upward to the outlet 54 as a spiraling vortexLThe collected solids separated by the cyclone separator 26 aredischarged with some fluid through the hydromotor valve 51 and-the check valve 53 into-the flow line 36, and'j'oin the'production of the I that the hydromotor valve 51, which is open when the electricity is on and closes automatically whenthe'electricity is off, prevents the cyclone separator 26 from' losing its fluid if the well 10 continues to produce gas when an electric failure occurs-and stops the pump means '28. The hydromotor sl is, of course,'an optional pieceof equipment and unnecessary when the conditioning unit 20 is utilized o'ncertain-wells. 3 f

Clean fluid which is discharged from the outlet 54 of the cyclone separator '26 proceeds through the gas eliminator 31 into the suction manifold 62 of the power driven pump means 28, such as the electric motor 58 and the multi-plex plunger pump 60. The outlet 64 of the pump 60 communicates through the desurger 65, which reduces the flow during the peak flow and adds to the minimum flow, with the power fluid intake 16 of the downwell pump 14 in the well 10, and, as long as the average pressure remains the same and the pump cycles remain constant over a period of time, provides substantially a constant volume of clean, high pressure fluid to be delivered to the downwell engine of the downwell pump 14.

At this point it should be noted that the downwell pump 14 discharging into the pressurized separator-accumulator tank 22 as the result of the horsepower created by the surface pump means 28 supplies the pressure that is used to make all of the components of the power fluid conditioning unit 20 of this invention function. Accordingly, it is unnecessary to use an auxilliary power source such as a centrifugal pump to charge the cyclone separator 26 and the pump 28. I

It should also be noted that it is extremely desirable to treat the clean, high pressure power fluid so that it will acquire lubricating, non-corrosive and other desired power fluid qualities. Accordingly, means 66, such as a chemical pump, may beprovided for discharging desired chemicals into the suction manifold 62 of the pump-60. v Y

The capacity of the downwell pump l4 may be controlled by varying its speed, and this may be affected by any suitable means for controlling the power fluid flow to the intake 16 from the outlet 64 of the pump 60. For

example, the power fluid flow may be varied by varying the speed of the pump 60 which can be done in a controlled manner; for instance when using an internal combustion engine, or it can be accomplished by a constant speed prime mover with a variable speed drive.

Exemplary means for' controlling the power fluid flow to thedownwell pump 14 from'the pump 60 is shown in FIGS. 1 and 2. Suitable by-pa'ss means 68 communicate betweenvalve means 30 and the inlet 52 of the cyclone separator 26. The valve means 30 controls the speed of the downwell pump 14 by passing back to the inlet 52 of the cyclone separator 26 a quantity of clean fluid, the amount of the fluid being bypassed controlling the amount of fluid sent to the well 1050 as to maintain the desiredstrokes per minute on the downwell pump 14.

As shown inFIG. 2, the power fluid conditioning unit 20 is preferably mounted upon a suitable skid 70 so that it is compact'and may be positioned as desired with respect to a well.

FIG; 6 is a graphical summary of the results of a testing program on the power fluid conditioning unit 20 of the present invention as utilized with a variety of downwell hydraulic pumps at differing pump setting depths. As can be seen, maximum pump displacement vs. pump setting depth is shown. Such data is based upon 50 percent water-cut production, 5 l inches casing, and a maximum well head operating pressure of 2500 p.s.i.

While certain preferred embodiments of the invention have been specifically illustrated and described, it is understood that the invention is not limited thereto, as many variations will be. apparent to thoseyskilled in the art, and the invention'is to be given its broadest interpretation within the terms of the following claims. v

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a downwell engine and pump unit which utilizes power fluid for pumping well fluid, such as oil, gas and,

water, from a well to a flow line, a one well, self contained, hydraulic pumping system comprising a power fluid conditioning unit to condition produced fluid from the produced well fluid and well exhausted power fluid so that it will be suitable for use as power fluid, which comprises: 1

a. a pressurized separator-accumulator tank which hausted power fluid and produced well fluid, the gravity separation of water from oil and gas taking place in said tank, said tank having at'least two main outlets therein, a first outlet communicating with said flow line, the volume of oil, gas and water produced by said well being substantially discharged therethrough, and a second outlet in the lower section of said tank for release of gravity separated water, oil, or mixture of oil and water;

b. a back pressure valve disposed between said flow line and said tank for controlling the pressure in said tank;

. at least one cyclone, centrifugal separator for conditioning fluid from said separator-accumulator tank by removing suspended solids therefrom, said cyclone separator having an inlet which communicates with said second outlet of said tank for receiving fluid from the lower section of saidtank at an optimum pressure so as to give a desired pressure drop across said cyclone separator for the requirements of a particular well, a first outlet connected with said flow line for passage of suspended solids separated by said cyclone separator with some fluid into said flow line, and a second outlet for thedischarge of conditioned fluid;

d. power driven pump means, the inlet thereof cornmunicating with said second outlet of said cyclone separator and the outlet thereof communicating with said downwell pump in said well and providing condition, high pressure fluid to be used as power fluid; and I v e. means to control the speed of said downwell pump by adjusting power fluid flow thereto from said power driven pump means so as to maintain the desired strokes permitted on said downwell pump;

2. The downwell engine and pump according to claim 1, wherein said means to control the speed of said downwell-pump comprise by-pass means communicating between said inlet of said cyclone separator and the outlet of said power driven pump means, and valve means, associated with said by-p'ass means which 'controls the speed of said downwell pump by passing back to said cyclone separator a quantity of clean fluid,-the

communicates with said well for receiving the excyclone separator'and being adapted to direct the inlet flow of fluid to be conditioned substantially tangentially to the inner surface of said side wall, and said second outlet being located in theupper end of said cyclone separator, whereby pressurized fluid to be conditioned enters'said inlet and'rotation thereof develops high centrifugal forces in said cyclone separator, drawingsuspended solids outward toward the side wall and downward in an accelerating spiral along the side wall to said apex and moving conditioned fluid inward and upward to said second outlet as a spiraling vortex, and the underflow of suspended solids separated by said cyclone separator are discharged 'with some fluid through said first outlet into said flow line.

4. The downwell engine and pump according to claim 1, wherein means are provided for discharging chemicals into the suction of said pump means so that the clean fluid passing therethrough acquires lubricatv 6. The downwell engine and pump according to claim l, wherein said power fluid conditioning unitis mounted upon a skid.

7. The downwell engine and pump according to claim' 1, wherein a check valve is positioned between the apex of said cyclone separator and said flow line to preclude a back flow of solids from said flow-'line'to said cyclone separator when said power fluid conditioning unit is shut down.

8. The downwell engine and pump according to claim 7, wherein said pump meanscomprises an elec tric motor driven pump. I

9. The downwell engine and pump according to claim 8, wherein a hydramotor valve, which is open when the'electricity .is on and which closes automatically when the electricity is off, is-positioned between said check valve and the apex of said cyclone separator so as to prevent said cyclone separator from losing fluid if an electrical failure occurs and stops said pump means and said well continues to produce gas. 

1. In a downwell engine and pump unit which utilizes power fluid for pumping well fluid, such as oil, gas and water, from a well to a flow line, a one well, self contained, hydraulic pumping system comprising a power fluid conditioning unit to condition produced fluid from the produced well fluid and well exhausted power fluid so that it will be suitable for use as power fluid, which comprises: a. a pressurized separator-accumulator tank which communicates with said well for receiving the exhausted power fluid and produced well fluid, the gravity separation of water from oil and gas taking place in said tank, said tank having at least two main outlets therein, a first outlet communicating with said flow line, the volume of oil, gas and water produced by said well being substantially discharged therethrough, and a second outlet in the lower section of said tank for release of gravity separated water, oil, or mixture of oil and water; b. a back pressure valve disposed between said flow line and said tank for controlling the pressure in said tank; c. at least one cyclone, centrifugal separator for conditioning fluid from said separator-accumulator tank by removing suspended solids therefrom, said cyclone separator having an inlet which communicates with said second outlet of said tank for receiving fluid from the lower section of said tank at an optimum pressure so as to give a desired pressure drop across said cyclone separator for the requirements of a particular well, a first outlet connected with said flow line for passage of suspended solids separated by said cyclone separator with some fluid into said flow line, and a second outlet for the discharge of conditioned fluid; d. power driven pump means, the inlet thereof communicating with said second outlet of said cyclone separator and the outlet thereof communicating with said downwell pump in said well and providing condition, high pressure fluid to be used as power fluid; and e. means to control the speed of said downwell pump by adjusting power fluid flow thereto from said power driven pump means so as to maintain the desired strokes permitted on said downwell pump.
 2. The downwell engine and pump according to claim 1, wherein said means to control the speed of said downwell pump comprise by-pass mEans communicating between said inlet of said cyclone separator and the outlet of said power driven pump means, and valve means associated with said by-pass means which controls the speed of said downwell pump by passing back to said cyclone separator a quantity of clean fluid, the amount of said fluid being by-passed controlling the amount of fluid sent to said well.
 3. The downwell engine and pump according to claim 1, wherein said cyclone, centrifugal separator comprises an inverted conical section, said first outlet being located at the apex thereof, said inlet being positioned in the side wall in the upper region of said cyclone separator and being adapted to direct the inlet flow of fluid to be conditioned substantially tangentially to the inner surface of said side wall, and said second outlet being located in the upper end of said cyclone separator, whereby pressurized fluid to be conditioned enters said inlet and rotation thereof develops high centrifugal forces in said cyclone separator, drawing suspended solids outward toward the side wall and downward in an accelerating spiral along the side wall to said apex and moving conditioned fluid inward and upward to said second outlet as a spiraling vortex, and the underflow of suspended solids separated by said cyclone separator are discharged with some fluid through said first outlet into said flow line.
 4. The downwell engine and pump according to claim 1, wherein means are provided for discharging chemicals into the suction of said pump means so that the clean fluid passing therethrough acquires lubricating, non-corrosive and other desired qualities.
 5. The downwell engine and pump according to claim 4, wherein said chemical discharge means comprises a chemical pump.
 6. The downwell engine and pump according to claim 1, wherein said power fluid conditioning unit is mounted upon a skid.
 7. The downwell engine and pump according to claim 1, wherein a check valve is positioned between the apex of said cyclone separator and said flow line to preclude a back flow of solids from said flow line to said cyclone separator when said power fluid conditioning unit is shut down.
 8. The downwell engine and pump according to claim 7, wherein said pump means comprises an electric motor driven pump.
 9. The downwell engine and pump according to claim 8, wherein a hydramotor valve, which is open when the electricity is on and which closes automatically when the electricity is off, is positioned between said check valve and the apex of said cyclone separator so as to prevent said cyclone separator from losing fluid if an electrical failure occurs and stops said pump means and said well continues to produce gas. 